6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
77 lines
2.6 KiB
C++
77 lines
2.6 KiB
C++
//===- llvm/ADT/STLFunctionalExtras.h - Extras for <functional> -*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains some extension to <functional>.
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//
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// No library is required when using these functions.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ADT_STLFUNCTIONALEXTRAS_H
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#define LLVM_ADT_STLFUNCTIONALEXTRAS_H
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#include "llvm/ADT/STLForwardCompat.h"
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#include <cstdint>
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#include <type_traits>
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#include <utility>
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namespace llvm {
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//===----------------------------------------------------------------------===//
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// Extra additions to <functional>
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//===----------------------------------------------------------------------===//
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/// An efficient, type-erasing, non-owning reference to a callable. This is
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/// intended for use as the type of a function parameter that is not used
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/// after the function in question returns.
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///
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/// This class does not own the callable, so it is not in general safe to store
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/// a function_ref.
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template<typename Fn> class function_ref;
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template<typename Ret, typename ...Params>
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class function_ref<Ret(Params...)> {
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Ret (*callback)(intptr_t callable, Params ...params) = nullptr;
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intptr_t callable;
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template<typename Callable>
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static Ret callback_fn(intptr_t callable, Params ...params) {
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return (*reinterpret_cast<Callable*>(callable))(
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std::forward<Params>(params)...);
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}
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public:
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function_ref() = default;
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function_ref(std::nullptr_t) {}
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template <typename Callable>
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function_ref(
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Callable &&callable,
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// This is not the copy-constructor.
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std::enable_if_t<!std::is_same<remove_cvref_t<Callable>,
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function_ref>::value> * = nullptr,
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// Functor must be callable and return a suitable type.
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std::enable_if_t<std::is_void<Ret>::value ||
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std::is_convertible<decltype(std::declval<Callable>()(
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std::declval<Params>()...)),
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Ret>::value> * = nullptr)
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: callback(callback_fn<std::remove_reference_t<Callable>>),
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callable(reinterpret_cast<intptr_t>(&callable)) {}
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Ret operator()(Params ...params) const {
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return callback(callable, std::forward<Params>(params)...);
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}
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explicit operator bool() const { return callback; }
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};
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} // end namespace llvm
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#endif // LLVM_ADT_STLFUNCTIONALEXTRAS_H
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